How to remove rust stains from irrigation water

Iron in irrigation water. Well water here carries dissolved iron you cannot see. When the sprinklers spray it onto a wall, driveway or fence, the iron meets the air, turns to rust and stays. UF/IFAS points out that most Florida well water is high in iron and that the orange streaks on buildings come from irrigating with it.

No. Pressure washing takes off dirt, mildew and algae, which sit on the surface. Rust is a chemical stain in the pores of the concrete or stucco, and water pressure alone barely touches it. Turning the pressure up to try usually etches the concrete before the rust moves.

No. Bleach is for mildew and algae. On rust it does nothing useful and can make the stain harder to remove. Rust needs an acid based rust remover.

With a rust remover made for concrete and masonry, used exactly as its label says. The general process:

• Test a small spot first, especially on colored concrete or pavers.
• Wet the plants and grass around it, and rinse them again afterward.
• Apply, let it work for the time on the label, then rinse thoroughly.
• Repeat on heavy stains rather than leaving it on longer.

If the same wall also has mildew, that part is a normal pressure cleaning job, and it is best done before the rust treatment.

Usually, with care. Stucco and painted walls need a gentler product and a test spot, because some removers lighten paint. Pavers can lighten too, so test somewhere hidden. Old, heavy stains may fade rather than disappear completely.

Keep the water off the hard surfaces, or take the iron out of it.

• Adjust the sprinkler heads so they water the lawn, not the wall or the driveway.
• Shorten run times so less water reaches anything it can stain.
• Treat the iron. UF/IFAS lists water softeners, oxidizing filters and combined chlorination and filtration systems as the options, and suggests testing the water through your county Extension office first.

Yes, if the sprinklers keep hitting the same spot with the same water. Removal without fixing the spray pattern or the iron just resets the clock.